拖动无边框窗体

实现效果：

　　

知识运用：

 　　API中的两个函数 　ReleaseCapture和SendMessage

        [DllImport("user32")]　　　　//用于向指定的窗体发送windows消息
        public static extern bool SendMessage(IntPtr hwdn,int wMsg,int mParaam,int IParam);

　　

实现代码：

        public const int WM_SYSCOMMAND = 0x0112;
        public const int SC_MOVE = 0xF010;
        public const int HTCAPTION = 0x0002;

        [DllImport("user32")]
        public static extern bool ReleaseCapture();
        [DllImport("user32")]
        public static extern bool SendMessage(IntPtr hwdn,int wMsg,int mParaam,int IParam);
        private void Form1_MouseDown(object sender, MouseEventArgs e)
        {
            ReleaseCapture();   //用来释放当前线程中某个窗口捕获的光标
            SendMessage(this.Handle,WM_SYSCOMMAND,SC_MOVE+HTCAPTION,0); //向Windows发送拖动窗体的消息
        }